After IC chips are formed on a semiconductor wafer (hereinafter, referred to as “wafer”), a probe test is performed on the wafer by using a probe apparatus in order to inspect electrical characteristics of the IC chips. The probe apparatus is configured to control a position of a wafer chuck which moves in X, Y and Z directions and rotates about a Z axis so that probes, i.e., probe needles, of a probe card are brought into contact with electrode pads of the IC chips of the wafer, the probe card being provided above the wafer chuck which mounts thereon the wafer.
In order to make the probes precisely contact with the electrode pads of the IC chips on the wafer, first, the wafer surface is imaged by a camera provided in the probe apparatus and, also, the probes are imaged by a camera provided at, e.g., the wafer chuck side. Next, based on the imaged positions of the wafer chuck, a so-called fine alignment is performed to calculate a position of the wafer chuck at which the electrode pads contact with the probes. In order to perform the fine alignment, a movement region of the wafer chuck needs to be ensured. However, as the wafer is scaled up, the movement region is expanded, so that the apparatus is scaled up. Further, the expansion of the movement region of the wafer chuck increases movement time and alignment time. Meanwhile, a demand for an improvement of throughput leads to a development of a loader unit capable of loading a plurality of carriers or a common loader unit shared by a plurality of inspection units. However, there is a trade-off relationship between a high throughput and a large occupation area of the apparatus.
As for a conventional probe apparatus aimed to provide a high throughput, there is known an apparatus described in Japanese Patent Laid-open Publication No. H6-66365 (Especially, FIG. 1). In this apparatus, two inspection units including a wafer chuck, a probe card and the like are connected to both sides of a loader unit. Since, however, the inspection units are not designed to be scaled down, the inspection units installed at both sides of the loader unit increase the occupation area of the probe apparatus. Further, the wafer transfer deteriorates due to the presence of a pincette for transferring a wafer from/to a carrier loaded into the loader unit and two swing arms for transferring the wafer between the pincette and the two inspection units, the pincette being movable in a longitudinal direction of the loader unit. Moreover, the moving paths of the swing arms need to be ensured, so that the apparatus cannot be scaled down.